Meaning
Analytical spectroscopy techniques establish a unique spectroscopic profile for raw polymer resins and compound blends. Procurement teams use chemical fingerprinting to verify that delivered plastic stock matches the specific resin grade and additive package stated in supplier quality certificates. The procedure relies on Fourier-transform infrared spectroscopy or gas chromatography mass spectrometry to detect structural impurities or unauthorized filler substitutes.
It governs raw material verification at the factory gate and stops applying once the material undergoes thermal degradation during downstream molding operations.
Analytical Protocol
Testing procedures compare infrared absorption spectra against baseline reference spectra provided by resin manufacturers. Laboratory technicians identify minor peaks corresponding to specific antioxidant packages or flame retardant additives. Discrepancy findings reveal batch variations.
Chemical fingerprinting isolates unauthorized resin recycling or grade substitution before processing begins.
Admissibility Threshold
Chinese judicial expertise centers require full spectral library records alongside certified calibration logs to accept spectral evidence in contractual disputes. Courts reject uncalibrated spectra. Submitting comparative spectral overlays establishes non-conforming delivery under civil code provisions governing contract quality defaults.
Claimants must provide unbroken chain-of-custody documentation for tested samples.
Verification Boundary
Spectral matching cannot distinguish between identical chemical compounds sourced from different licensed chemical plants. The method detects functional group shifts rather than molecular weight distribution changes. Polymer degradation during storage alters oxidation peaks and can generate false non-conformance readings.
